Two Showers three boards

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sirsparkabit

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Hi guys a little senario i very rarely come across , i will be very glad if you think my solution is o.k. here we go----------

Extended two circuits which are on main board (no rcd so am changing this to 17th ed as you would.

Small board with main switch for first shower 6mm cable 30 amp rewirable, so will incorperate this shower into new board,no problem with exceding rating of main switch in new board.

Second Shower in small Conactum unit 63A main switch 40A breaker(no rcd) so should i leave as is and mark down on comments on existing installation on my cert no rcd reqires upgrading,or change for shower unit with Rcd and charge accordingly.

I dont want two showers fed from same board if i can help it:O

Suppply fuse is 60/80A dont know which yet. :_|

 
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I maintain a student house. There is a rcd main switch board (in addition to others) that has 8, 32a breakers, each feeding a shower in 8 of the rooms. There is a further combi boiler which supplies the whole house heating and the shower and bathroom for the other 3 rooms without showers. 100A head. No faults or tripping in the 6 years i have been involved.

 
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Although we are not allowed diversity for an electric shower, EDF were not interested in the 8 showers in 8 all electric studio flats we are converting at present. Not interested in the 8, 2kw instant water heaters or the lights or 2 ring hob. The only thing the engineer wanted to know was the 8, 2kw convector heaters for estimating the new 3 phase supply.

 
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The last big job I did had a 9kw and 10.5 kw shower. I put them on a seperate Rcd protected board. Main fuse was 100 amp but if people buy 10.5 kw showers and main fuse is only 60 amp I always get it upgraded to be on te safe side. I always think it would be at christmas when everything is being used the main fuse will go.

batty

 

kme

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Last time I did a property with three 10.8KW showers on 100A s/p supply, I installed a contactor arrangement which only allowed one shower to work at a time.

Must admit, it felt weird wiring the pullcords in 1.0mm T+E:)

Could you imagine someone going in after, and not reading the notes????? Classic

 

sirsparkabit

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Popping them in together on new board they have not taken out the main fuse yet so i suppose they have proved themselves thanks guys.

P.s might hang me clamp meter on while they are running, ohh mrs.

 

davetheglitz

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Last time I did a property with three 10.8KW showers on 100A s/p supply, I installed a contactor arrangement which only allowed one shower to work at a time. Must admit, it felt weird wiring the pullcords in 1.0mm T+E:)

Could you imagine someone going in after, and not reading the notes????? Classic
I like that solution!

I assume you had two NC contacts in series with each pullcord switch to do this.

Did you have just one double pole isolator for the three showers - would seem to make sense.

How did you explain it to the owner?

 

DonkeyDong

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hi all,

guys, look at the characteristics of the fuse - it will happily run for a while over its rating (don't have my book with me). Some people do worry too much. ;)

D.

 

sirsparkabit

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hi all,guys, look at the characteristics of the fuse - it will happily run for a while over its rating (don't have my book with me). Some people do worry too much. ;)

D.
Yes worrying is in my genes always like other brains to pick its so sensible to bounce things around:D

 

cheggers

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run them off the same board

it is getting to be a common thing nowadays.

as donkeydong said the fuse will be fine.

the chances of both showers being used for any lengh of time at the same time is minimal

 

sirsparkabit

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run them off the same board it is getting to be a common thing nowadays.

as donkeydong said the fuse will be fine.

the chances of both showers being used for any lengh of time at the same time is minimal
thanks for all replies guys:)

 

kme

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I like that solution! I assume you had two NC contacts in series with each pullcord switch to do this.

Did you have just one double pole isolator for the three showers - would seem to make sense.

How did you explain it to the owner?
No - went a bit further, and had 3 11pin relays, and 2 40A contactors. Meant that:

1. the 3rd set of contacts on the relay made for a failsafe system.

2. Rather than master / slave / slave, each shower was equal. As soon as a pullcord was operated; the associated shower was the only one which had juice.

As an added advantage, the customers HAVE to get into the habit of switching off the pullcord after use.

 

kme

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run them off the same board it is getting to be a common thing nowadays.

as donkeydong said the fuse will be fine.

the chances of both showers being used for any lengh of time at the same time is minimal
BUT you cannot apply diversity to elec. showers. IF they are both used together; along with another one medium appliance, the service fuse goes.

Customer may call DNO out to replace, and THEY will condemn your work as sub-standard.

I would not put two loads of this size on a standard supply

Just my opinion

 

Admin1

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BUT you cannot apply diversity to elec. showers. IF they are both used together; along with another one medium appliance, the service fuse goes. Customer may call DNO out to replace, and THEY will condemn your work as sub-standard.

I would not put two loads of this size on a standard supply

Just my opinion
I agree, Sir.

 

steptoe

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BUT,

its fine to run a 200A electric welder from your 13a socket even tho on strike it will pull nigh on 80amps!!!!! for a split milli sec, and after about an hour you will actually get flames from the socket purely down to the continuous 13 amp draw!!!!! (its actually prob more like 15amps TBH.)

believe me, I know from very personal experience many moons ago,

NOT recommended. :( :( :(

 
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